Big Sur Ventana/SilverPeak Garmin Trailmap
Many trail/camp locations on USGS/USFS/WildernessPress/NationalGeographic/Garmin maps of the Big Sur Ventana & Silver Peak Wilderness Areas are incorrect - this Garmin-format version of the on-line Big Sur Trailmap provides accurate trail and camp locations based on local knowledge (mostly GPS'd), and also locally-known "use trails", water sources, waterfalls, and other features in the Ventana and Silver Peak Wilderness areas and in Big Sur state parks.
Mac users: Since I do not have a Mac, I can't provide detailed instructions for its map transfer,
but the "direct GPS installation" procedure should be similar to that described for a Windows PC.
If you can provide additional information, please let me know via email at
or by a forum posting.
|SMALL SIZE LINES & ICONS||MEDIUM SIZE LINES & ICONS||LARGE SIZE LINES & ICONS|
Wilderness hikers take note:
You cannot assume that wilderness trails will be passable and
followable - the trail may be blocked by brush or downfall and/or
its tread may not be apparent, especially for secondary trails and
"use" trails. Brush grows quickly in these wilderness area,
trails along steep slopes are subject to erosion, fire-damaged tree
fall can be extensive, animal tracks can be more prominent than the
actual trail, etc. And trail maintenance is spotty.
Hiker-reported trail conditions are available in the on-line VWA Trail
Reports Forum. Know before you go - you may be very glad
you did! I've encountered too many hikers who had no clue
regarding the difficulties they were going to encounter and who did
not end up with the enjoyable wilderness experience they had
anticipated. A primary aim of this trailmap is to allow hikers
to more easily use (and enjoy) difficult wilderness trails
by providing accurate trail data -
where tread is sporadic and/or confusion with animal tracks possible,
use of a GPS loaded with accurate trail data is recommended!
|Maps are updated weekly - last update:||Map Update History|
Direct GPS Install
Direct GPS Install
Direct GPS Install
Direct GPS Install
Direct GPS Install
Direct GPS Install
Instructions for Direct installation into GPS using a Windows PC:
(uses direct PC-to-GPS data transfer via USB):
(A Mac should also be able to transfer the map file to a GPS using direct PC-to-GPS USB transfer in a similar fashion, but not having access to a Mac I cannot be sure of this.)
(These instructions work for the GPSs I own - if you find a different procedure is needed for your unit, or have a procedure which works for a Mac, send me the details and I will add them here).
Note: the following procedure is quicker and easier than methods using MapSource/BaseCamp software, but not as safe - for example, you could mistakenly delete a needed system file on the the GPS! Please follow the instructions carefully and exactly - haste makes waste!
 You must put your GPS into "USB Mass Storage" mode,
which directly connects the GPS memory/storage to the PC. First
turn your GPS off, then connect a USB cable from your GPS to your PC. Then
On a GPSMAP60:
Turn GPS on, select "Main Menu" -> "Setup" -> "Interface" -> "USB Mass Storage" (a "PC-cabled-to-GPS" screen will appear when USB Mass Storage mode is entered)
On an Oregon, GPSMAP62, and eTrex 20/30:
The GPS will automatically turn on - wait for a "USB Mass Storage mode" screen to appear (either a PC-cabled-to-GPS or a horizontally-pointing trident, sort of)
| Wait for the PC to recognize that a new device has been attached, which is often indicated by a beep from the PC. On many PCs, a pop-up will then display an "Autoplay" window - you should then click "Open folder to view files using Windows Explorer" which will open at the (highlighted) GPS device -- its name is GPS model and PC specific, an example being "Garmin Oregon (G:)". It's subdirectories should be displayed, one of which will be "Garmin" (sometimes capitalized). If that pop-up does not appear, you must then open your PC's "Windows Explorer" program and find the GPS device that has been installed. If the device's subdirectories are not displayed, then expand (click on the "+") to reveal the "Garmin" subdirectory. And if your GPS has a microSD card, that device should also be displayed in Windows Explorer, e.g as "Removeable Disk (H:)", and should also have a "Garmin" subdirectory.|
| Use Windows Explorer to copy the Garmin-format Trailmap file you downloaded, "BigSurTrailmapWithTopo.IMG" or "BigSurTrailmapSansTopo.IMG", to a "Garmin" subdirectory on your GPS, either in the GPS memory or on the microSD card memory (if installed).|
| This special step is NOT NEEDED for newer GPSs such as GPSMAP 62, Oregon, and eTrex 20/30 - do not do this step unless you know it is necessary! It is needed for older units, such as the GPSMAP60 and pre-20/30 eTrex, which can only have one active map file (though that one file can contain many different individual maps) which must have the Garmin-determined name "gmapsupp.img" (sometimes capitalized). If yours is such a GPS, it may already have an existing "gmapsupp.img" file in its "Garmin" directory, in which case it must be replaced with the BigSurTrailmap file - if you wish to preserve that old map data for use at a later time, you must then EITHER (1) rename it on the GPS (e.g. to old-gmapsupp.img) OR (2) move it to the PC for storage OR (3) do both for safety (recommended!). If you do not wish to preserve it, then delete it. Now re-name the "BigSurTrailmapWithTopo.IMG" or "BigSurTrailmapSansTopo.IMG" file just loaded onto the GPS's Garmin directory to "gmapsupp.img", so it will become the active map.|
| Instead of simply unplugging the GPS from the USB cable, to safely remove the USB-enabled GPS it's best to, on the Windows PC, click on the "Open/Close Devices" icon (often a little USB plug and green circle with check mark inside, which should have appeared when the USB Mass Storage mode was established), then click "Eject USB Mass Storage Device" or "Eject (your device name)" , then after the "Safe to remove hardware" message appears the GPS can be disconnected from the USB cable.|
| Re-start the GPS - the Big Sur Trailmap should now display in the Big Sur region. On newer GPS's, one can choose to enable/disable individual map files, generally via "Main Menu" -> "Setup" -> "Map" -> "Map Information". The Big Sur Trailmap will be indicated by "BigSurTrailmap" - and on some units, e.g. an Oregon, additional "BigSurTrailmap" maps will be found if you installed the version with topography+streams (these maps can be "enabled" or "disabled" individually if desired via the menu). For additional information see How To Change Which Map Is Displayed On A Garmin GPS.|
| The Big Sur Trailmap only takes 1 MB of storage SANS Topography and 44 MB WITH Topography, so if you have a newer GPS and plan to hike Big Sur again, you can just "disable" it as described in the last step, so it can be simply "enabled" on your next hike. On an older GPS, which required special step  above, if you wish to preserve the Big Sur Trailmap for later use you can follow the above steps to again connect the GPS to the PC in USB Mass Storage mode and use Windows Explorer to go to your GPS's "Garmin" directory and reverse special step , i.e. re-name "gmapsupp.img" to "BigSurTrailmapWithTopo.IMG" or "BigSurTrailmapSansTopo.IMG" and then restore the original "gmapsupp.img" - or if you wish to restore your GPS to its original condition, then delete the Big Sur Trailmap from your GPS's "Garmin" directory.|
Instructions for Installation into Garmin BaseCamp/MapSource Software using a Windows PC:
First ensure that BaseCamp and MapSource are not running! Then run (execute) the downloaded installation file "BigSurTrailmapWithTopo_install.exe" or "BigSurTrailmapSansTopo_install.exe" and follow its popup instructions - this creates a "BigSurTrailmap" background option in BaseCamp/MapSource (selected via the dropdown menu on the left side of the upper toolbar). I am not going to treat BaseCamp/MapSource software use - you can find a brief tutorial at the following link: How To Load Maps On My Garmin GPS Unit (which includes instructions for a Mac). Note: you can uninstall the Big Sur Trailmap from BaseCamp/MapSource by using your PC's "Control Panel" program deletion capabiliy.
Garmin-format Trailmap Usage:
|•||Lines: Five different trail/road lines are displayed: trails (green+white), use trails (orange+black), dirt gated (red+white) and ungated (red) roads, and paved roads (gray). Trail and road lines are non-solid so they cannot be confused with user tracks on the GPS, using colors similar to those on the on-line Big Sur Trailmap. The trail/road name is displayed when the map pointer is over it.|
|•||Icons: POI (Point of Interest) icons identical to the on-line Big Sur Trailmap icons represent camps (green tent), use camps (white tent), vehicle-access campgrounds (tan tent), water sources (drinking glass), summits (purple peak), and waterfalls (blue waterfall). The icon name is displayed when the map pointer is over it.|
|•||Search: POI names can be found using the Garmin "Find"/"Where To" feature, either alphabetically or by category. For the latter, they are "Geographic Points" with subcategories "Manmade Places" [camps, use camps, campgrounds] or "Water Features" [water sources, waterfalls] or "Land Features" [summits]. Also, trailheads and roadends are listed under "Geographic Points - Land Features". Warning: if another map is also loaded, such as Garmin's "Topo24K", a search will also find its features, which may have the name of a Trailmap feature but be incorrectly located, even if that map is "disabled"!|
|•||Zoom Levels: Not all features are displayed at all zoom levels, and this behavior can be changed by GPS setup options (but does not seem to work exactly the same on different GPSs). So far as I can tell, the trail/usetrail/road lines are always displayed, but the contour lines only appear at smaller scales. Different icons also appear only at smaller scales, but different icons can appear/disappear at different zoom levels.|
|•||Labels: Both the lines and icons have names, which can be displayed by moving the map pointer over the line/icon. In addition, the trails/usetrails/roads have their name automatically displayed on the map at intervals (though that can be turned off if desired - see below). To save space I've used abbreviations, which can be a bit cryptic. Unfortunately, the GPS can change my letter capitalizations, so "VDC" may become "Vdc".|
|•||User control: The levels at which icons appear/disappear and the label text size can be controlled under "Setup" -> "Map" with then further menus depending upon the GPS (e.g. "Advanced Map Setup" on the Oregon and GPSMAP62) which control the "Zoom Levels", "Detail Level", and "Text Size". I'm not really sure how all these work or interact with each other. I do know that a "trail" and "use trail" are considered "streets", so if their persistent map labels bothers you, you can turn off "street labels" - but that does not affect the "roads", for which the labels remain in place!|
|•||Contour and stream lines [for "With Topo" files]: Contour lines are displayed at 20-ft elevation intervals. These utilize the most accurate digital terrain data available, comparable to a 1:24000 quadrangle map, but cannot show small-scale ridges and gullies. The elevation is displayed when the map pointer is over a contour line. Blue lines depict streams, with intermittent/perennial streams being thin/thick. Stream location data is not as accurate as the topographic data (it is based on 1:100000 maps) - if the topography shows a gully but the depicted stream is displaced from that gully then likely the actual stream location is in the gully.|
|•||Vehicular roads: The Big Sur Trailmap is intended for hiking, hence the only roads displayed are those which might be used as connectors between trails or for trailhead access. For the "sans topography" version, another map loaded onto your GPS can provide additional roads since such will be displayed through the trailmap's transparent background (but it may also display roads/trails/etc which do not actually exist!).|
|•||Trailhead/Roadhead POIs: To provide a greater variety of destination locations, I've created searchable POIs for each trailhead and road end with names ala "Abbreviated Name N/E", with the N/E tail indicating that this trailhead (roadhead) lies North and East of the other one, which would be "Abbreviated Name S/W". These trailhead POIs are displayed as a small black pushpin icon on the map when zoomed in at high map resolutions, in addition to the usual on-line Trailmap icons. To keep them from cluttering the "Geographic Points - Manmade Places" POI category which lists camp POIs, I've created them under "Geographic Points - Land Features".|
Jan 2013: My hiking tests find that for slow hiking speeds and
poor GPS reception, as often occurs in Big Sur, the Garmin algorithm
can have difficulty determining when a trail point has been passed,
leading to egregious along-trail "distance to destination" errors -
since it thinks you should go back to a point actually passed, the
error is twice the distance to the passed point. (This
also occurs for Garmin-provided maps, and is particularly apt to occur
in a series of switchbacks.) The current Garmin-format Trailmap uses a
work-around to reduce the errors, generally to below 0.1 mile.
Nevertheless, please note that the compass arrow will not
always point in the "forward" direction and the "distance to
destination" can go up-and-down, being too large when the compass
arrow is pointing backward. Some models provide a "route
re-calculation" selection, which when used will always give the
correct distance for the current location - alternately, you can "stop
navigation" and then "resume navigation" or "find a new destination"
and then select the same point. A separate issue is that the ETA (Estimated
Time of Arrival) is usually not useful since I've found Garmin simply
assumes a speed of 3 mph in "Pedestrian" mode, which is
unlikely to be correct when hiking/backpacking in the wilderness (and
even larger speeds are utilized by the "Cycling" and
"Automobile" modes). Finally, the GPS-calculated
along-trail "distance to destination" is around 3-4% smaller than the
values I calculate from the same data, e.g. on the route metrics
calculation webpage, apparently due to truncation error - since
the trailmap trail lines themselves underestimate the actual distance
by around 2-3% (as they do not include every small-scale twist and
turn along a trail), if I want a truer along-trail "distance to
destination" I mentally add 5% (i.e. the displayed distance divided by
10 and then again by 2) to the displayed GPS value. Caveat
ambulator! Using along-trail routing requires some GPS
knowledge, so you may find "direct (straight-line) routing" simpler to
use and less confusing - another benefit of that mode is its useable
ETA, since it uses the computed rate-of-change in straight-line
distance to the destination and hence does depend upon one's actual
Trails and roads are routable, meaning that within the map coverage area you can can choose a destination (for example by selecting any point along a trail or by a "Find" or "Go To" of a POI) and then select "Go" to have the shortest along-trail route to that point be calculated and displayed. Routing works in BaseCamp/MapSource as well as on the GPS itself.
But you should be able to find your way in the wilderness without needing a GPS to tell you how to get there! My primary reason for providing this capability is the along-trail distance to the destination which can be displayed as you hike along, instead of the straight-line distance produced by direct "Off Trail" routing.
For this feature to work your GPS's routing options must be set to "Follow Roads", i.e. not to "Direct" or "Off Trail". Additionally, because this map is intended for hikers it uses the "Activity" setting in a unique way, requiring some GPS-sophistication to utilize. "Use trails" can be of questionable hikeability, so some people may not want to attempt using them and would not want a routing containing them. Therefore "use trails" are not used in any routing using "Automobile"> or "Cycling"> modes, whereas they will be used with the "Pedestrian" mode. [However, I have experienced some flakiness with "use trails" sometimes being used in "Automobile" mode, hence I've also given "Cycling" mode the equivalent functionality - experimentation with your unit may be necessary.] Note that on some models you can have a default routing mode, e.g. "Pedestrian", but once a route has been selected and displayed the "Find" key can then be used to change to another "Activity"; alternatively, you can have opt to have the unit prompt you for the desired "Activity" each time you create a new route.
In any event, should the automatically created start-to-finish routing not be what you want, you can create a custom route using "via" points you explicitly select.
The "routable" feature is new and not extensively tested - if you have comments, positive or negative, you can make a forum posting for myself and others to read.
|•||Trail conditions: Remember that the Ventana/SilverPeak Wilderness Areas are in fact wilderness - trail conditions are highly variable and water sources can be seasonal. You should obtain current information before heading out! Links to the latest trail condition reports and water information are available in the on-line Big Sur Trailmap or in the VWA Trail Reports forum.|
If you can provide corrections or additions to this webpage, or if you have an opinion regarding this
Garmin-format version and how it might be improved, email Jack Glendening at:
or post to the forum.